Redescription of the zooxanthellateEudendrium moulouyensis(Eudendriidae: Hydrozoa) from the Mediterranean Sea

Abstract

Eudendrium moulouyensis is a zooxanthellate hydroid originally described from the Chafarinas Islands (Alboran Sea, south-western Mediterranean) in summer 1991. According to the original description, this species can be identified due to the occurrence of symbiotic zooxanthellae in the entire endodermal layer of the colony (gastrodermis and tentacle endodermis), a unique feature among the Mediterranean Eudendrium species. However, several aspects of its life cycle and the extent of its phenotypical variability are still unknown. Since winter 2004, colonies of E. moulouyensis were recorded throughout the year from 0.5 m to 30 m depth from the southern Adriatic Sea (Otranto Channel) and the Gibraltar Strait (Alboran Sea). Additional specimens were collected from the northern Adriatic (Vis, Croatia), Sicily Channel (Pantelleria and Lampedusa Islands), and western Sardinia (Costa Paradiso). These findings offered the opportunity to describe for the first time the full life cycle and to elucidate several biological aspects related to phenotypical variation of colony morphology, vertical zonation, seasonality, zooxanthellae–polyp relationship, and cnidome morphology and distribution. The number and morphology of male gonophores per reproductive polyp is described here for the first time, providing a useful taxonomic character to easily discriminate Myrionema amboinense from E. moulouyensis. From the available information, the occurrence of M. amboinense in the Mediterranean Sea should be regarded as doubtful, if they are not accompanied by observations of cnidome, male gonophores or distinctly separate tentacles whorls.

Missing species among Mediterranean non-Siphonophoran Hydrozoa

“…Biodiversity research has a long history the Mediterranean Sea, one of the best-known seas globally (Coll et al 2010 ; Gravili et al 2013 ). In particular, the diversity of Mediterranean Hydrozoa is well known and has been recently updated (Bouillon et al 2004 , 2006 ; Schuchert 2005 , 2006 , 2008a , b , 2009 , 2010 ; Galea 2007 ; De Vito et al 2008 ; Gravili et al 2007 , 2008 , 2010 , 2013 ; Morri et al 2009 ; Mastrototaro et al 2010 ). The biodiversity of the Mediterranean Sea is high due to ecological, historical, and paleogeographic reasons (Sarà 1985 ; Bianchi and Morri 2000 ; Bianchi 2007 ).…”

Long‐term changes in hydroid (Cnidaria, Hydrozoa) assemblages: effect of Mediterranean warming?

“…Hydroids typical of the Southern Mediterranean were recorded for the first time in the area studied: Eudendrium moulouyensis , a species originally described from Morocco (Marques et al. 2000) and recently observed in Southern Italy (De Vito et al. 2008) was frequent and reproductive.…”

A unified assessment of marine Mediterranean assemblages: a lesson from benthic hydroids

“…), Western Sardinia, the Sicily channel and the Adriatic Sea (De Vito et al . ). In the present study, E .…”

“…De Vito et al . () pointed out the wide distribution of Eudendrium moulouyensis in the Mediterranean, suggesting a correlation with the rise in sea‐surface temperature in the basin. This hydroid hosts symbiotic zooxanthellae whose growth would be facilitated by a clear and warm sea.…”